123 lines
3.1 KiB
Python
123 lines
3.1 KiB
Python
class Node:
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def __init__(self, key):
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self.key = key
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self.left = None
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self.right = None
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class BST:
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def __init__(self):
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self.root = None
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def insert(self, key):
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if self.root is None:
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self.root = Node(key)
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else:
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self._insert(self.root, key)
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def _insert(self, node, key):
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if key < node.key:
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if node.left is None:
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node.left = Node(key)
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else:
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self._insert(node.left, key)
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elif key > node.key:
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if node.right is None:
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node.right = Node(key)
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else:
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self._insert(node.right, key)
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def search(self, key):
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if self.root is None:
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return False
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else:
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return self._search(self.root, key)
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def _search(self, node, key):
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if node is None:
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return False
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elif node.key == key:
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return True
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elif key < node.key:
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return self._search(node.left, key)
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else:
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return self._search(node.right, key)
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def preorder(self):
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if self.root is None:
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return
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else:
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self._preorder(self.root)
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print()
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def _preorder(self, node):
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if node is None:
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return
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print(node.key, end=" ")
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self._preorder(node.left)
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self._preorder(node.right)
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def breadthfirst(self):
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if self.root is None:
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return
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else:
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self._breadthfirst(self.root)
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print()
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def _breadthfirst(self, node):
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if node is None:
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return
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queue = []
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queue.append(node)
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while len(queue) > 0:
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print(queue[0].key, end=" ")
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node = queue.pop(0)
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if node.left is not None:
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queue.append(node.left)
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if node.right is not None:
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queue.append(node.right)
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def remove(self, key):
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if self.root is None:
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return
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else:
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self._remove(self.root, key)
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def _remove(self, node, key):
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if node is None:
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return node
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if key < node.key:
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node.left = self._remove(node.left, key)
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elif key > node.key:
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node.right = self._remove(node.right, key)
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else:
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if node.left is None:
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temp = node.right
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node = None
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return temp
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elif node.right is None:
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temp = node.left
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node = None
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return temp
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temp = self._minValueNode(node.right)
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node.key = temp.key
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node.right = self._remove(node.right, temp.key)
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return node
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def _minValueNode(self, node):
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if node is None:
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return node
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while node.left is not None:
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node = node.left
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return node
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if __name__ == "__main__":
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Tree = BST()
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keys = [5, 9, 1, 3, 7, 4, 6, 2]
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for key in keys:
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Tree.insert(key)
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Tree.preorder() # 5 1 3 2 4 9 7 6
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Tree.breadthfirst() # 5 1 9 3 7 2 4 6
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